Rood et al. U.S. Pat. No. 6,364,936 provides for selective sorption and desorption of gases with electrically heated activated carbon fiber cloth element. In the '936 patent, an adsorption/desorption unit includes a hollow enclosure containing one or more elongated hollow elements of activated carbon fiber cloth (ACFC) of appropriate length to cross sectional area to provide suitable electrical resistance for heating. The elements conduct electrical current to heat to a temperature that permits selective adsorption of a gas stream constituent and subsequent desorption to recover sorbate. An enclosure houses the ACFC elements and is arranged to direct gas stream flow through the elements and into and out of the enclosure via gas ports. The ability to heat the elements to a desired temperature by electrical current flow allows for straightforward implementation of selective adsorption. After an adsorption step, altering the temperature of the element or elements enables desorption. In a particularly preferred embodiment, the enclosure with the element also includes a liquid, condensate outlet and liquid sorbate is directly recovered as liquid from the same unit used for adsorption and desorption.
Rood et al. U.S. Patent Application 20090293725 provides a steady state tracking desorption system and method. In the '725 application, a steady state tracking desorption system achieves steady tracking of either a fixed sorbate output set point, or a set point that changes over time. The system includes an electrically heated thermal adsorption/desorption device. A temperature sensor senses the temperature of an adsorbent material within the adsorption/desorption device. A sorbate sensor senses a sorbate concentration from an outlet of the adsorption/desorption device. A power sensor senses the power supplied by the desorption device. A controller interprets levels sensed by the temperature sensor, the sorbate sensor and the power sensor and provides a signal to achieve steady set point tracking of a sorbate concentration from the outlet of the adsorption/desorption device.
There are several industrial processes that use or produce difficult to capture organic and inorganic gases. These organic and inorganic gases are often inert components of the gas streams of various manufacturing processes. They are typically present at low concentration in the effluent gas streams of the manufacturing processes. Due to these low concentrations, the organic gases are typically not reused in the process and are instead captured downstream or disposed of via a thermal oxidizer.